PURPOSE: To prevent trouble in an image forming device such as jamming in an arrangement in which a sheet material specifically formed as folded into an envelope shape is fed by a sheet material feeding device to the image forming device.

CONSTITUTION: Two types of rotary bodies are provided, i.e., energized rotary bodies 22, 23 and active rotary bodies 30, 32, 33 to feed each sheet material P within a sheet material feeding device M1, among which at least either member of either pair is arranged being split at the two ends of the sheet material P across the width. Thereby the two side edges E1 of the sheet material P to be fed can strongly be pressed partially, which permits feeding to an image forming device M2 upon making perfect the foldings at the edges.